Several years ago I decided I wanted to open my soda cans only half way. I no longer remember what insanity made me want to do this, but once I decided I wanted to, I kept at it. You’d think it’d be easy enough–just stop pulling on the tab when it’s half open. I was just so used to popping it all the way, though, that it was a challenge to pop it only half way. It comes naturally to me now; I don’t even have to think about it. But for those first weeks when I was learning, it took more effort–conscious effort–to stop the tab half way than it did just opening the can normally.
Popping the tabs half way did turn out to be handy, though, as now I always know exactly which can is mine.